Cisco Broadband Cable Command Reference Guide

Chapter 5 Cable CPE Commands
cable-modem upstream preamble qpsk
OL-1581-05
cable-modem upstream preamble qpsk
To enable the QPSK modulation scheme in the upstream direction from the cable interface to the CMTS,
use the cable-modem upstream preamble qpsk command in cable interface configuration mode. To
disable upstream modulation for the interface, use the no form of this command.
Cisco uBR904, uBR905, uBR924, uBR925 cable access routers, Cisco CVA122 Cable Voice Adapter
cable-modem upstream preamble qpsk
no cable-modem upstream preamble qpsk
Syntax Description This command has no arguments or keywords.
Defaults Enabled
Command Modes Interface configuration (cable interface only)
Command History
Examples The following example shows how to configure the cable interface for QPSK modulation on the
upstream:
Related Commands
Release Modification
11.3(4)NA This command was introduced for the Cisco uBR904 cable access router.
12.0(4)XI1 Support was added for the Cisco uBR924 cable access router.
12.1(3)XL Support was added for the Cisco uBR905 cable access router.
12.1(5)XU1 Support was added for the Cisco CVA122 Cable Voice Adapter.
12.2(2)XA Support was added for the Cisco uBR925 cable access router.
Router(config)# interface cable-modem 0
Router(config-if)# cable-modem upstream preamble qpsk
Router(config-if)#
Command Description
cable-modem compliant bridge Enables DOCSIS-compliant transparent bridging for the cable
interface at startup.
cable-modem downstream
saved channel
Modifies the saved downstream channel setting and upstream power
value on the cable interface.
cable-modem fast-search Enables a faster downstream search algorithm on the cable
interface.
cable-modem voip best-effort Allows voice calls to be sent upstream over the cable interface via
best effort.
Cisco Broadband Cable Command Reference Guide
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